1. Field of the Invention
This invention relates to tools and methods used to raise and space trusses and particularly to a single tool and method for raising and spacing trusses.
2. Description of the Prior Art
In modern frame construction, roofs are typically supported by a series of trusses. These are usually made of wood or metal, and have a complex structure. They must be positioned above the top story of a building at regularly spaced intervals. Trusses typically have a lower beam called a tie plate that holds the lower angled ends of a truss together. This plate is positioned on the top plates of the top story and secured in place. This often requires two or three workers. First, the truss is raised into position and clamped to the proper location. Then, it is secured with nails or other fasteners. The next truss is then raised and must be positioned at the proper interval, 24 inches for example. This requires measurements to verify that the proper spacing is accomplished. Then, the truss can be secured as before. This procedure is repeated for each truss in the roof system. Bear in mind that this work is done two or more stories in the air, often working on the top plates or ladders while moving heavy, awkward work pieces.
Tools to help raise and space trusses have been invented over the years to assist in the process. Some of these are found in the following U.S. Pat. No. 3,201,874, to Christy teaches a bar that has finger-type two spring clamps on the ends. The tool is used by placing the first finger clamp on a member already in position and then placing a second member in the second spring clamp. Once secured, the second member is in the proper position for fastening. The tool has a fixed bar for only one spacing and cannot be used to raise a truss. U.S. Pat. No. 5,161,345 to Sobjack, Sr. teaches a strap that has nail holes at regularly spaced apart intervals. This device is used by first erecting and securing the two outermost trusses of the building. Then, the remaining trusses are raised and stacked against one of the standing trusses. Then, the strap is unrolled and fixed to the two outermost trusses. Once the strap is extended, the remaining trusses are moved, one by one, to their positions and aligned with the nail hole in the strap. Once all the trusses are fixed in place, the strap is not removed. Rather, it becomes a permanent part of the roofing system. U.S. Pat. No. 5,628,119 to Bingham et al. teaches a device similar to that of the Christy patent above. In Bingham, the device is adjustable so that it can be set for different spacing. Note that both Christy and Bingham are to be used in general framing and are not limited to working with trusses. U.S. Pat. No. 6,993,882 to Crawford et al. teaches a brace that is made at a fixed spacing. It is used to ensure proper spacing of trusses and is designed as a brace to be left in place as part of the roofing system. It cannot be used to help raise trusses into an upright position. Finally, U.S. Pat. No. D318,785 to Dean teaches a truss spaced that is similar to the Christy patent with minor differences in the clamp shape.
All of these patents teach tools useful for spacing trusses, but not for raising trusses. Some tools exist for raising trusses, but these are poles that are used to push trusses into an upright position from below; they cannot be used to space the trusses. Thus, there is a need for tool that can be used to help raise trusses and space them that is not intended to be left in place, so that it can be used repeatedly.